Influence of maternal diabetes mellitus on fetal iron status

Associations between maternal metabolic conditions and neurodevelopmental conditions in offspring: the mediating effects of obstetric and neonatal complications

BACKGROUND

Maternal pre-gestational diabetes (PGDM), gestational diabetes mellitus (GDM), and overweight/obesity have been associated with increased risks of offspring neurodevelopmental conditions (NDCs) including autism, intellectual disability (ID), and attention deficit/hyperactivity disorder (ADHD). Less is known about whether and how obstetric and neonatal complications (e.g., preterm birth, neonatal asphyxia) could mediate these associations.

METHODS

In this Swedish register-based cohort study, we examined complications during pregnancy, delivery, and the neonatal period as potential mediators of the relationships between maternal metabolic conditions and offspring NDCs. We quantified the extent to which these obstetric and neonatal factors could mediate the associations of maternal metabolic conditions with offspring NDCs by applying parametric regression models for single mediation analyses and weighting-based methods for multiple mediation analyses under counterfactual frameworks.

RESULTS

The study sample included 2,352,969 singleton children born to 1,299,692 mothers from 1987-2010 who were followed up until December 31, 2016, of whom 135,832 children (5.8%) were diagnosed with at least one NDC. A substantial portion of the association between maternal PGDM and children's odds of NDCs could be explained by the combined group of obstetric and neonatal complications in the multiple mediation analysis. For instance, these complications explained 44.4% of the relationship between maternal PGDM and offspring ID risk. The proportion of the relationship between maternal overweight/obesity and children's risk of NDCs that could be explained by obstetric and neonatal complications was considerably smaller, ranging from 1.5 to 8.1%. Some complications considered on their own, including pregnancy hypertensive diseases, preterm birth, neonatal asphyxia, and hematological comorbidities, could explain at least 10% of the associations between maternal PGDM and offspring NDCs. Complications during the neonatal period showed a stronger joint mediating effect for the relationship between PGDM and offspring NDCs than those during pregnancy or delivery.

CONCLUSIONS

Obstetric and neonatal complications could explain nearly half of the association between maternal PGDM and offspring risk of NDCs. The mediating effects were more pronounced for complications during the neonatal period and for specific complications such as pregnancy hypertensive diseases, preterm birth, neonatal asphyxia, and hematological comorbidities. Effective preventive strategies for offspring NDCs should holistically address both the primary metabolic issues related to PGDM and the wide array of potential complications, especially those in the neonatal period.

The impact of maternal diabetes on the future health and neurodevelopment of the offspring: a review of the evidence

Maternal health during gestational period is undoubtedly critical in shaping optimal fetal development and future health of the offspring. Gestational diabetes mellitus is a metabolic disorder occurring in pregnancy with an alarming increasing incidence worldwide during recent years. Over the years, there is a growing body of evidence that uncontrolled maternal hyperglycaemia during pregnancy can potentially have detrimental effect on the neurodevelopment of the offspring. Both human and animal data have linked maternal diabetes with motor and cognitive impairment, as well as autism spectrum disorders, attention deficit hyperactivity disorder, learning abilities and psychiatric disorders. This review presents the available data from current literature investigating the relationship between maternal diabetes and offspring neurodevelopmental impairment. Moreover, possible mechanisms accounting for the detrimental effects of maternal diabetes on fetal brain like fetal neuroinflammation, iron deficiency, epigenetic alterations, disordered lipid metabolism and structural brain abnormalities are also highlighted. On the basis of the evidence demonstrated in the literature, it is mandatory that hyperglycaemia during pregnancy will be optimally controlled and the impact of maternal diabetes on offspring neurodevelopment will be more thoroughly investigated.

Umbilical cord management - the first opportunity to improve healthcare disparities

This review focuses on iron deficiency and iron deficiency anemia in women and children in the United States. These are common, fixable problems that disproportionally affect minority populations. There are many opportunities for successful screening and management. The knowledge and awareness for identification and treatment of our populations' commonest deficiency is crucial.

Effect of exposure to maternal diabetes during pregnancy on offspring's brain cortical thickness and neurocognitive functioning

Little is known about the long-term effects of maternal diabetes during pregnancy (DP), either gestational diabetes or preexisting diabetes (type 1 or type 2), on offspring's brain morphometry and neurocognitive functioning (NCF). This study examined the effect of prenatal exposure to maternal DP on the brain structure and NCF in children between 9 and 10 years of age. This study used cross-sectional neuroimaging and NCF data from the baseline wave of the Adolescent Brain and Cognitive Development® study. Exposure to maternal DP was assigned from the developmental history questionnaire. Differences in the brain cortical thickness (CTh) and five cognitive abilities (executive function, working and episodic memory, processing speed, and language abilities) were examined in diabetes-exposed and diabetes-unexposed children. Linear mixed effect models and generalized linear models were used to adjust for the effect of confounding variables. A total of 9,967 children (718 diabetes-exposed and 9249 unexposed) were included in the analysis. Diabetes-exposed children had lower whole-brain CTh [mean: exposed vs unexposed = 2.725 mm vs 2.732 mm; difference (95%CI): -0.007 mm (-0.013, -0.001)] compared to unexposed children after adjusting for confounding variables. Diabetes-exposed children had lower CTh in most part of the occipital lobe of both hemispheres, right postcentral gyrus, and left superior parietal cortex. Diabetes-exposed children also had lower scores in processing speed task [mean difference (95%CI): -1.7 (-2.8, -0.6)] and total cognition [mean difference (95%CI): -0.6 (-1.2, -0.02)]. Diabetes-exposed children have reduced CTh and NCF during preadolescence, which might have implications for psychomotor development during later life. Prospective studies are needed to confirm our findings.

Emotional Prosodies Processing and Its Relationship With Neurodevelopment Outcome at 24 Months in Infants of Diabetic Mothers

Gestational diabetes mellitus (GDM) is one of the most common complications of pregnancy. Hyperglycemia of pregnancy is a risk not only for later obesity of the offspring but also do harm to their neurodevelopment from fetus. An ERP research has shown that children with autism spectrum disorder (ASD) was characterized by impaired semantic processing. In this study, we used event-related potential (ERP) to assess the procession of different emotional prosodies (happy, fearful, and angry) in neonates of diabetic mothers, compared to the healthy term infants. And to explore whether the ERP measure has potential value for the evaluation of neurodevelopmental outcome in later childhood. A total of 43 full-term neonates were recruited from the neonatology department of Peking University First Hospital from December 1, 2017 to April 30, 2019. They were assigned to infants of diabetic mothers (IDM) group (n = 23) or control group (n = 20) according to their mother's oral glucose tolerance test's (OGTT) result during pregnancy. Using an oddball paradigm, ERP data were recorded while subjects listened to deviation stimulus (20%, happy/fearful/angry prosodies) and standard stimulus (80%, neutral prosody) to evaluate the potential prognostic value of ERP indexes for neurodevelopment at 24 months of age. Results showed that 1) mismatch response (MMR) amplitudes in IDM group were lower than the control; 2) lower MMR amplitude to fearful prosody at frontal lobe was a high risk for increased Modified Checklist for Autism in Toddlers (M-CHAT) scores at 24 months. These findings suggests that hyperglycemia of pregnancy may influence the ability to process emotional prosodies in neonatal brain; it could be reflected by decreased MMR amplitude in response to fearful prosody. Moreover, the decreased MMR amplitude at the frontal lobe may indicated an increased risk of ASD.

Maternal diabetes and the role of neonatal reticulocyte hemoglobin content as a biomarker of iron status in the perinatal period

AIMS

We aimed to evaluate the effects of maternal diabetes on neonatal iron status, measuring erythrocyte indices including hemoglobin, hematocrit, reticulocytes, mean corpuscular volume (MCV), percent (%) hypochromia, ferritin, and additionally mean reticulocyte hemoglobin content (MCHr) as an early marker of iron deficiency, and examine the association between neonatal MCHr, red cell indices, and ferritin.

MATERIALS AND METHODS

We conducted a hospital-based prospective cohort study in a tertiary neonatal unit of a University Hospital from 2018 to 2020. We enrolled 126 maternal-infant pairs of mothers whose pregnancy was associated with diabetes and 74 maternal-infant pairs from uncomplicated pregnancies. Erythrocyte indices were analyzed within the first twelve hours after birth. Erythrocyte parameters were compared between infants of the diabetes and the non-diabetic group. We examined the correlation of the neonatal MCHr with perinatal characteristics, including gestation, birth weight, maternal body mass index, the erythrocytic indices, maternal diabetes, maternal obesity, prematurity, small-for-gestational-age status, maternal preeclampsia, and maternal anemia. Finally, we evaluated the discordance between neonatal MCHr and neonatal ferritin.

RESULTS

Infants of the diabetes group had a significantly lower MCHr (32.6 pg vs. 34.2 pg, p=0.003) compared with infants of uncomplicated pregnancies. Neonatal MCHr was significantly correlated with maternal hypochromia (r=-0.237, p=0.004) and neonatal MCV (r=0.674, p<0.001). Neonatal MCHr was significantly associated with maternal diabetes [standardized coefficients 0.21, 95% confidence interval (CI) 0.05-0.58, p=0.003) and maternal preeclampsia (standardized coefficients 0.17, 95% CI 0.02-0.92, p=0.019), after adjusting for maternal anemia, maternal obesity, prematurity, and small-for-gestational-age status. Those results were consistent also when analyzing maternal-infant pairs with pre-existing diabetes, and maternal-infant pairs with gestational diabetes. There was significant discordance between neonatal MCHr and neonatal ferritin (p=0.001).

CONCLUSIONS

MCHr was significantly lower in infants of mothers whose pregnancy was associated with diabetes compared with infants of non-diabetic mothers and correlated with neonatal and maternal red cell indices of iron deficiency. Since there was significant discordance between neonatal MCHr and ferritin during the first postnatal day, it is possible that MCHr could be used as a screening test for iron deficiency, especially in infants.

Selective morphological and volumetric alterations in the hippocampus of children exposed in utero to gestational diabetes mellitus

Prior epidemiological studies have found that in utero exposure to gestational diabetes mellitus (GDM) is associated with increased risk for neurodevelopmental disorders. However, brain alterations associated with GDM are not known. The hippocampus is pivotal for cognition and emotional regulation. Therefore, we assessed relationships between in utero exposure to GDM and hippocampal morphology and subfield structure during childhood. One hundred seventeen children aged 7–11 years (57% girls, 57% exposed to GDM), born at Kaiser Permanente Southern California, participated in the BrainChild Study. Maternal GDM status was determined from electronic medical records. Children underwent brain magnetic resonance imaging. Freesurfer 6.0 was used to measure hippocampal and individual hippocampal subfield gray matter volume (mm³). Morphological analyses on the hippocampal surface were carried out using shape analysis. GDM‐exposed children exhibited reduced radial thickness in a small, spatially‐restricted portion of the left inferior body of the hippocampus that corresponds to the CA1 subfield. There was a significant interaction between GDM‐exposure and sex on the right hippocampal CA1 subfield. GDM‐exposed boys had reduced right CA1 volume compared to unexposed boys, but this association was no longer significant after controlling for age. No significant group differences were observed in girls. Our results suggest that GDM‐exposure impacts shape of the left hippocampal CA1 subfield in both boys and girls and may reduce volume of right hippocampal CA1 only in boys. These in‐depth findings illuminate the unique properties of the hippocampus impacted by prenatal GDM‐exposure and could have important implications for hippocampal‐related functions.

Motor Developmental Outcomes in Children Exposed to Maternal Diabetes during Pregnancy: A Systematic Review and Meta-Analysis

Studies on the association of maternal diabetes with motor development in children provide inconsistent findings. We searched MEDLINE/PubMed, EMBASE, Emcare, PsycINFO, and Google Scholar databases for primary observational, case-control, or cohort studies that report on the motor development of children exposed to maternal diabetes during pregnancy. Quality appraisal and data extraction were performed independently and in duplicate. A meta-analysis of summary measures was performed using random-effect models. Eighteen studies were identified for inclusion, however, only 13 were included in the meta-analysis. Exposure to maternal diabetes during pregnancy was associated with a lower pooled motor development in children and a decrease in both gross and fine motor development. Among all other factors, pre-existing diabetes and other gestational comorbidities, such as hypertension and obesity, or low socioeconomic status, also affect child development. Therefore, among children of diabetic mothers, those with other gestational comorbidities or pre-existing diabetes were more likely to be at risk developmentally.

Fetal chronic hypoxia and oxidative stress in diabetic pregnancy. Could fetal erythropoietin improve offspring outcomes?

Oxidative stress is responsible for microvascular complications (hypertension, nephropathy, retinopathy, peripheral neuropathy) of diabetes, which during pregnancy increase both maternal and fetal complications. Chronic hypoxia and hyperglycemia result in increased oxidative stress and decreased antioxidant enzyme activity. However, oxidative stress induces also anti-oxidative reactions both in pregnant diabetes patients and in their fetuses. Not all type 1 diabetes patients with long-lasting disease develop microvascular complications, which suggests that some of these patients have protective mechanisms against these complications. Fetal erythropoietin (EPO) is the main regulator of red cell production in the mother and in the fetus, but it has also protective effects in various maternal and fetal tissues. This dual effect of EPO is based on EPO receptor (EPO-R) isoforms, which differ structurally and functionally from the hematopoietic EPO-R isoform. The tissue protective effects of EPO are based on its anti-apoptotic, anti-oxidative, anti-inflammatory, cell proliferative and angiogenic properties. Recent experimental and clinical studies have shown that EPO has also positive metabolic effects on hyperglycemia and diabetes, although these have not yet been fully delineated. Whether the tissue protective and metabolic effects of EPO could have clinical benefits, are important topics for future research in diabetic pregnancies.

Suggested use of sensitive measures of memory to detect functional effects of maternal iodine supplementation on hippocampal development

Maternal hypothyroxinemia secondary to iodine deficiency may have neurodevelopmental effects on the specific neurocognitive domain of memory. Associated disruption of thyroid hormone-dependent protein synthesis in the hippocampus has the potential to result in compromised development of the structure with consequential impairments in memory function. Despite links between maternal iodine deficiency during gestation and lactation and abnormal hippocampal development in rat fetuses and pups, there has been little research on the specific function of memory in human infants and young children born to iodine-deficient mothers. Several candidate measures have proven to be sensitive to the effects of gestational iron deficiency on memory function in infants and young children, including habituation and dishabituation, imitation-based tasks, and event-related potentials. Such measures could be used to test the effects of maternal iodine supplementation on the specific neurocognitive domain of memory in infants and young children. Furthermore, progress in understanding the effects of maternal iodine supplementation on neurocognitive development could be accelerated by the development of a nonhuman primate model to complement the rodent model.

Weight-related and analytical maternal factors in gestational diabetes to predict birth weight and cord markers of diabetic fetopathy

OBJECTIVE

The objective was to determine the value of clinical and analytical maternal factors to predict birth weight and umbilical cord biochemical markers of diabetic fetopathy.

METHODS

Prospective evaluation of gestational diabetes pregnancies (n = 50). Maternal weight-related clinical and analytical factors were collected during pregnancy. After birth, an umbilical cord sample was taken.

RESULTS

Univariate linear regression analysis showed relationship between maternal weight, glycated hemoglobin (HbA1c) and insulin-like growth factor 1 (IGF1) with birth weight percentile. A significant association was found between maternal weight and cord insulin and C-peptide. Maternal HbA1c, leptin and insulin during pregnancy showed a positive linear association to cord leptin, insulin and C-peptide. In multivariate analysis models, final maternal BMI showed an independent positive association with cord C-peptide.

CONCLUSIONS

Maternal weight-related and analytical parameters show diagnostic value to birth weight and cord markers.

Gestational Diabetes: Long-Term Central Nervous System Developmental and Cognitive Sequelae

Gestational diabetes is a common complication of pregnancy and occurs in approximately 7% of all pregnancies. It has been associated with an increased rate of congenital anomalies including disturbances of intrauterine growth, delayed brain maturity, and neurobehavioral abnormalities in the offspring. The resulting maternal and fetal metabolic dysfunction leads to diminished iron stores (which can affect red blood cell [RBC] production and subsequent organogenesis), a metabolism-placental perfusion mismatch, increased FFA, increased lactic acidosis, and potential hypoxia. Though most newborns born in the context of gestational diabetes are not significantly affected by it, empirical research suggests gestational diabetes has been associated with lower general intelligence, language impairments, attention weaknesses, impulsivity, and behavioral problems. In extreme cases, it may essentially function as a gestational brain insult. Children who are exposed to poorly controlled gestational diabetes may benefit from some form of tracking or follow-up assessments. Additionally, clinicians evaluating children with developmental learning or cognitive dysfunction may want to seek appropriate gestational diabetes-related information from the parents. A greater understanding of this significant gestational risk may help foster improved prenatal diabetes management and may help reduce the neurodevelopmental effects of gestational diabetes.

Gestational age-specific reference ranges of hepcidin in cord blood

BACKGROUND

Iron deficiency (ID) contributes to anaemia of prematurity, and hence the reliable assessment of iron nutrition status appears to be mandatory.

OBJECTIVE

To establish gestational age (GA)-specific reference ranges for hepcidin concentrations in cord blood [Hep(CB)] of preterm and term infants and to identify pre- and perinatal confounding factors.

METHODS

This is a prospective observational study including 221 infants (GA at birth: 24-42 weeks). Hep(CB) along with complete blood counts, ferritin and parameters of inflammation and clinical data were recorded. Data are presented as medians (IQR).

RESULTS

The Hep(CB) of very preterm infants (GA <30 weeks, n = 40) was 26.9 ng/ml (13.5-63.1), for moderately preterm infants (GA 30-36 weeks, n = 81) it was 45.9 ng/ml (24.7-74.5) and for term infants (GA ≥37 weeks, n = 100) it was 103.9 ng/ml (61.4-149.2). The Hep(CB) of infants with ID was lower [36.9 ng/ml (18.0-58.3)] than that of iron-replete infants [86.6 ng/ml (51.9-143.8)]. The Hep(CB) of infants delivered by elective caesarean section was lower [38.3 ng/ml (15.5-73.7)] than that of infants after spontaneous vaginal delivery or secondary caesarean section [80.3 ng/ml (48.5-137.6)]. Infants with a standard deviation score for birth weight (SDSBW) <-2 had a lower Hep(CB) [23.1 ng/ml (11.7-61.5)] compared to infants with SDSBW ≥-2 [71.1 ng/ml (34.0-121.7)]. The highest Hep(CB) (437.6 ng/ml) was recorded in an infant with Enterococcus faecalis sepsis. Multiple logistic regression analysis confirmed ferritin, GA and mode of delivery as important factors associated with Hep(CB).

CONCLUSION

This is the first report on GA-specific reference ranges for Hep(CB) in preterm infants. Whereas iron stores, GA and mode of delivery were associated with Hep(CB), the association with inflammation and intra-uterine growth retardation was less clear.

Birth weight and perceived stress reactivity in older age

Stress reactivity is a disposition that underlies individual differences in stress responses, thereby affecting vulnerability for the development of disease. Besides genetic and early postnatal environmental factors, stress reactivity has been shown to be influenced by an adverse prenatal developmental environment, but it is unclear if such effects persist into older age. We tested associations between fetal growth and perceived stress reactivity in 421 participants from the Hertfordshire Cohort at age 66-75 years. Regression analysis showed a U-shaped association between birth weight and perceived stress reactivity with increased levels of stress reactivity at the lower and upper end of the birth weight distribution. These effects were stable after adjustment for markers of early adversity and recent adversity and chronic stress. Although the effects were small, they are consistent with findings from studies in younger cohorts, and demonstrate that such effects can persist into older age.

Novel red cell indices indicating reduced availability of iron are associated with high erythropoietin concentration and low ph level in the venous cord blood of newborns

There is evidence that an elevated erythropoietin (EPO) concentration is associated with signs of iron deficient erythropoiesis. The aim of this study was to evaluate the iron status by means of novel cellular indices and serum iron markers and to determine whether these are associated with EPO and pH in the venous cord blood of 193 full-term newborns. There were positive correlations between EPO and the percentage of hypochromic red blood cells (%HYPOm) and reticulocytes (%HYPOr) [r = 0.45 (p < 0.001) and r = 0.56 (p < 0.001), respectively]. %HYPOm and %HYPOr also had negative correlations with pH [r = -0.53 (p = 0.001) and r = -0.46 (p = 0.001), respectively]. Newborns who had low pH (pH < or =7.15, n = 16) had significantly higher %HYPOm, %HYPOr, and serum transferrin receptor and transferrin concentrations in their cord blood than newborns with normal pH. Thus, in newborn cord blood, the higher number of red cells and reticulocytes with lower Hb content may have impaired the oxygen carrying capacity that has been a trigger for EPO production. Furthermore, signs of lower hemoglobinization of red cells are associated with low umbilical vein pH in the newborns, indicating an increased risk of birth asphyxia.